WO2019227546A1

WO2019227546A1 - Method for preparing ink-jet printing amoled display panel

Info

Publication number: WO2019227546A1
Application number: PCT/CN2018/092356
Authority: WO
Inventors: 何昆鹏; 张晓星
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2018-05-29
Filing date: 2018-06-22
Publication date: 2019-12-05
Also published as: CN108832009A

Abstract

Provided in the present invention is a method for preparing an ink-jet printing AMOLED display panel, comprising the following steps: preparing a TFT backplate, and preparing an anode on the TFT backplate; preparing an interval layer on the anode; preparing a pixel defining layer on the TFT backplate, wherein the pixel defining layer covers the interval layer; performing patterning on the pixel defining layer for forming a notch in the pixel defining layer so as to expose the interval layer; etching off the interval layer below the notch through an etching liquid so as to expose the anode; and forming an ink layer on the anode through an ink-jet printing method. By means of the present invention, the degree of cleanliness of a surface of an anode in an AMOLED display panel can be improved, and the residue is reduced, so that a printed light-emitting layer is unfolded more easily and uniformly, display abnormalities of the AMOLED display panel are avoided, the surface structure of a pixel defining layer is not damaged, and loss of the surface thickness and line width of the pixel defining layer can be avoided.

Description

Preparation method of inkjet printing AMOLED display panel

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on May 29, 2018, with application number 201810528668.1, and the invention name is "A method for preparing an inkjet printed AMOLED display panel". Citations are incorporated in this application.

Technical field

The invention relates to the field of display technology, in particular to a method for preparing an inkjet printed AMOLED display panel.

Background technique

In the evaporation-active AMOLED (Active-Matrix Organic Light Emitting Diode) technology, the film thickness of the evaporation material in the pixel area is good, and IJP-AMOLED (Inkjet Printing AMOLED) uses Water-based liquid ink is sprayed into a film, and the residue of the hydrophobic PDL (Pixel Define Layer) material in the Bank area (pixel area) directly affects the spread of the ink, resulting in abnormal pixel functions and ultimately affecting the display effect. For example, as shown in FIG. 1, 1 'is a TFT (Thin Film Transistor) backplane, 2' is a flat layer, 3 'is a pixel definition layer, and 4' is an anode. As shown in FIG. 2, 30 ′ is a patterned pixel definition layer. A notch 31 ′ is formed thereon. The anode 4 ′ is exposed through the notch 31 ′, and the pixel definition layer material 32 ′ remains on the anode 4 ′. As shown in FIG. 3, when the ink layer 5 'is formed on the anode 4' by inkjet water (the ink material may be a material for light emission), there will be a blank area 41 'around the remaining pixel definition layer material 32'. Covered by the ink layer 5 ', which will affect the display effect of AMOLED.

Therefore, good ink spreadability largely determines the product quality of IJP-AMOLED, so it is particularly important that the Bank area is clean and free of residues before printing ink. The PDL material is an organic photosensitive material. The Bank region is formed by the yellow light and OVEN process (baking process). After the PDL layer is developed, the PDL material residue in the pixel region directly affects the ink spread. At present, the countermeasures for the residual PDL material of the vapor-deposited AMOLED pixel region are more dry etching after the PDL yellow light process is used. However, the dry etching process after the PDL yellow light process of IJP-AMOLED will bring the following problems:

1. Dry etching will destroy the surface structure of PDL and make PDL lose its hydrophobicity. Therefore, the ink dripped during the IJP process is likely to adhere to the surface of the Bank area instead of flowing into the Bank area.

2. Dry etching will cause a certain degree of loss in the thickness and line width of the PDL, which will affect the confirmation of the ink drop amount and the pixel aperture ratio.

Summary of the Invention

In order to solve the above technical problems, the present invention provides a method for preparing an inkjet printed AMOLED display panel, which can improve the cleanliness of the anode surface in the AMOLED display panel, reduce residues, and make the printed light-emitting layer easier to spread uniformly, so as to avoid AMOLED display panel display The abnormality will not damage the surface structure of the pixel definition layer, nor will it cause loss of the surface thickness and line width of the pixel definition layer.

The invention provides a method for preparing an inkjet printed AMOLED display panel, including the following steps:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

Preparing a spacer layer on the anode to isolate the anode from the pixel definition layer;

Preparing a pixel definition layer on the TFT backplane, and the pixel definition layer covers the spacer layer;

Patterning the pixel definition layer and forming a gap on the pixel definition layer to expose the spacer layer;

Etching the spacer layer under the notch through an etching solution to expose the anode;

An ink layer is formed on the anode by means of inkjet printing.

Preferably, the thickness of the spacer layer ranges from 300 to 800 Angstroms.

Preferably, the spacer layer is a metal film layer, and the anode is a transparent electrode or a reflective electrode.

Preferably, the transparent electrode is an ITO film layer, and the reflective electrode includes two ITO film layers and a silver metal layer sandwiched between the two ITO film layers.

Preferably, after patterning the pixel definition layer, the method further includes the following steps:

A baking process is performed on the pixel definition layer and the anode.

Preferably, the spacer layer is a molybdenum film layer or an aluminum film layer, and the spacer layer under the notch is etched away by an aluminum etching solution.

Preferably, the pixel definition layer is patterned by a yellow light process.

Preferably, the pixel definition layer is a hydrophobic pixel definition layer.

Preferably, the following steps are further included:

A flat layer is prepared on the TFT backplane, and the pixel definition layer and the anode are both located on the flat layer.

Preferably, forming an ink layer on the anode by means of inkjet printing, specifically:

A hole layer and a light emitting layer are sequentially formed on the anode by inkjet printing; wherein the hole layer includes a hole injection layer and a hole transport layer, and the hole transport layer is located at the hole injection. Between the layer and the light emitting layer.

The invention also provides a method for preparing an inkjet printed AMOLED display panel, including the following steps:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

Forming an ink layer on the anode by means of inkjet printing;

The thickness of the spacer layer ranges from 300 to 800 Å;

The spacer layer is a metal film layer, and the anode is a transparent electrode or a reflective electrode.

A baking process is performed on the pixel definition layer and the anode.

Preferably, the pixel definition layer is patterned by a yellow light process;

The pixel definition layer is a hydrophobic pixel definition layer.

Preferably, the following steps are further included:

Preparing a flat layer on the TFT back plate, and the pixel definition layer and the anode are located on the flat layer;

Forming an ink layer on the anode by inkjet printing is specifically:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

A pixel definition layer is prepared on the TFT backplane, and the pixel definition layer covers the spacer layer; the pixel definition layer is a hydrophobic pixel definition layer;

Forming an ink layer on the anode by means of inkjet printing;

Forming an ink layer on the anode by inkjet printing is specifically:

Preferably, the thickness of the spacer layer ranges from 300 to 800 Angstroms;

Preferably, the transparent electrode is an ITO film layer, and the reflective electrode includes two ITO film layers and a silver metal layer sandwiched between the two ITO film layers;

After graphicizing the pixel definition layer, the following steps are further included:

Performing a baking process on the pixel definition layer and the anode;

The spacer layer is a molybdenum film layer or an aluminum film layer, and the spacer layer under the notch is etched away by an aluminum etching solution.

Preferably, the pixel definition layer is patterned by a yellow light process;

The method for preparing an inkjet printed AMOLED display panel further includes the following steps:

The implementation of the present invention has the following beneficial effects: The present invention prepares a spacer layer on the anode surface on the TFT backplane, and after the pixel definition layer above the spacer layer is etched away, there are pixels remaining on the surface of the spacer layer. Define the layer material. The spacer layer is etched away by an etching solution, thereby removing the pixel definition layer material remaining on the surface of the spacer layer, thereby improving the cleanliness of the anode surface and reducing the residue, making it easier to print the light-emitting layer to spread uniformly, so as to avoid AMOLED The display panel displays abnormally. Moreover, the present invention does not increase the dry etching process, will not damage the surface structure of the pixel definition layer, and will not cause loss of the surface thickness and line width of the pixel definition layer.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without paying creative labor.

1 is a schematic diagram of an anode and a pixel definition layer prepared on a TFT backplane in the prior art;

FIG. 2 is a schematic structural diagram obtained by the pixel definition layer in FIG. 1; FIG.

3 is a schematic diagram of preparing an ink layer on the anode in FIG. 2;

4 is a flowchart of a method for manufacturing an inkjet printed AMOLED display panel according to the present invention;

5 is a schematic diagram of an anode, a spacer layer, and a pixel definition layer prepared on a TFT backplane provided by the present invention;

FIG. 6 is a schematic structural diagram obtained by graphically defining the pixel definition layer in FIG. 5 provided by the present invention; FIG.

FIG. 7 is a schematic structural diagram obtained by etching the spacer layer under the notch of the pixel definition layer in FIG. 6 provided by the present invention; FIG.

8 is a cross-sectional view of an ink layer prepared on the anode in FIG. 7 provided by the present invention;

FIG. 9 is a top view of an ink layer prepared on the anode in FIG. 7 provided by the present invention; FIG.

10 is a schematic structural diagram of an anode according to an embodiment of the present invention;

FIG. 11 is a schematic structural diagram of an ink layer provided by the present invention.

Detailed ways

The invention provides a method for manufacturing an inkjet printed AMOLED display panel. As shown in FIG. 4, the method includes the following steps:

Referring to FIG. 5, a TFT (Thin Film Transistor) backplane 1 is prepared, and an anode 4 is prepared on the TFT backplane 1.

A spacer layer 5 is provided on the anode 4 to isolate the anode 4 from the pixel definition layer.

A pixel definition layer 3 is prepared on the TFT backplane 1, and the pixel definition layer 3 covers the spacer layer 5.

As shown in FIG. 6, the pixel definition layer 3 is patterned, and a notch 31 is formed on the pixel definition layer 3 to expose the spacer layer 5. 30 in FIG. 6 is a pixel definition layer after patterning.

As shown in FIG. 7, the spacer layer 5 under the notch 31 is etched away by an etching solution, and the pixel definition layer material 32 remaining on the spacer layer 5 is taken away to expose the anode 4; the surface of the anode 4 is flat and there is no residue The pixels define layer material 32 or other residues. 50 shown in FIG. 7 is that the anode 4 is exposed after the spacer layer 5 under the notch 31 is etched away by an etching solution.

As shown in FIG. 8, an ink layer 6 for emitting light is formed on the anode 4 by means of inkjet printing. It can be seen from FIG. 9 that the ink layer 6 spreads well on the surface of the anode 4, and the ink layer 6 can spread evenly and evenly on the surface of the anode 4, thereby improving the display effect of the AMOLED display panel.

In the present invention, after the pixel definition layer is patterned, there is no need to add a dry etching process, so the surface structure of the pixel definition layer will not be damaged, and the thickness and line width of the pixel definition layer will not be lost.

Further, the thickness of the spacer layer 5 ranges from 300 to 800 Angstroms.

Further, the spacer layer 5 is a metal film layer, and the anode 4 is a transparent electrode or a reflective electrode.

In an embodiment, as shown in FIG. 10, the reflective electrode includes two ITO film layers 41 and a silver metal layer 42 sandwiched between the two ITO film layers 41. In another embodiment, the transparent electrode is an ITO (Indium Tin Oxide) film layer.

The AMOLED display panel in the present invention may be top-emitting or bottom-emitting. When the AMOLED display panel is top-emitting, the light emitted from the AMOLED display panel passes through a cathode opposite to the anode. At this time, the anode is a reflective electrode and the cathode is a transparent electrode . When the AMOLED display panel emits light at the bottom, the light emitted from the AMOLED display panel passes through the anode. At this time, the anode is a transparent electrode and the cathode is a reflective electrode.

Further, the graphic pixel definition layer 3 further includes the following steps:

The patterned pixel definition layer 30 and the anode 4 are subjected to a baking process. The pixel definition layer can be cured through the baking process, and the amorphous ITO film layer in the anode 4 can be converted into a crystalline ITO film. Floor.

Further, the spacer layer 5 is a molybdenum film layer or an aluminum film layer, and the spacer layer 5 under the notch 31 of the pixel definition layer is etched away by using an aluminum etching solution.

Further, the pixel definition layer 3 shown in FIG. 5 is patterned by a yellow light process. Generally speaking, the yellow light process includes coating a photoresist on the pixel definition layer, exposing, developing, and etching the pixel definition layer.

Further, the pixel definition layer is a hydrophobic pixel definition layer.

Further, the method for preparing an inkjet printed AMOLED display panel further includes the following steps:

A flat layer 2 is prepared on the TFT back plate 1, and the pixel definition layer 3 and the anode 4 are both located on the flat layer 2.

Further, forming the ink layer 5 on the anode 4 by means of inkjet printing is specifically:

The hole layer 62 and the light emitting layer 61 shown in FIG. 11 are sequentially formed on the anode 4 by inkjet printing. The hole layer 62 includes a hole injection layer 622 and a hole transport layer 621. The hole transport layer 621 It is located between the hole injection layer 622 and the light emitting layer 61.

Preferably, the active layer of the thin film transistor on the TFT backplane 1 may be a low temperature polysilicon material or an oxide material such as IGZO (Indium Gallium Zinc Oxide), or other semiconductor materials.

In summary, in the inkjet printed AMOLED display panel provided by the present invention, after the anode of the TFT backplane is completed, a spacer film formation, yellow light, and etching process is added, and then the yellow light and The baking process, and finally the spacer layer is etched away with an aluminum etching solution.

As the etching rate of the spacer layer by the aluminum etchant can reach

The spacer layer of a certain thickness can be etched clean in a short time, and the anisotropy of the wet etch also ensures that the small amount of pixel definition layer material remaining on the surface of the spacer layer will not cause the spacer layer to be etched uncleanly.

The amorphous ITO film layer also forms a crystalline ITO film layer during the baking process of the pixel definition layer. The aluminum etching solution will not react with the crystalline ITO film layer, so the invention can ensure that the interval is etched away. Layer and take away the material of the remaining pixel definition layer without affecting the anode film layer.

The invention can improve the cleanliness of the surface of the anode film layer in the AMOLED display panel and reduce the residue, so that the printed light-emitting layer can be more easily spread uniformly, so as to avoid abnormal display of the AMOLED display panel.

Moreover, the film-forming process, the yellow-light process, and the etching process that increase the spacer layer are all ordinary processes, and there is no special requirement for equipment and materials, so the present invention can greatly improve the product yield with a small increase in cost.

The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without deviating from the concept of the present invention, several simple deductions or replacements can be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

A method for preparing an inkjet printed AMOLED display panel includes the following steps:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

Preparing a spacer layer on the anode to isolate the anode from the pixel definition layer;

Preparing a pixel definition layer on the TFT backplane, and the pixel definition layer covers the spacer layer;

Patterning the pixel definition layer and forming a gap on the pixel definition layer to expose the spacer layer;

Etching the spacer layer under the notch through an etching solution to expose the anode;

An ink layer is formed on the anode by means of inkjet printing.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 1, wherein the thickness of the spacer layer ranges from 300 to 800 Angstroms.
The method of claim 1, wherein the spacer layer is a metal film layer, and the anode is a transparent electrode or a reflective electrode.
The method for preparing an inkjet printed AMOLED display panel according to claim 3, wherein the transparent electrode is a layer of ITO film, and the reflective electrode comprises two layers of ITO film and sandwiched between the two layers of ITO film Silver metal layer between layers.
The method for preparing an inkjet printed AMOLED display panel according to claim 4, further comprising the following steps after patterning the pixel definition layer:

A baking process is performed on the pixel definition layer and the anode.
The method for preparing an inkjet printed AMOLED display panel according to claim 5, wherein the spacer layer is a molybdenum film layer or an aluminum film layer, and the spacer layer under the notch is etched away by an aluminum etching solution.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 1, wherein the pixel definition layer is patterned by a yellow light process.
The method of claim 1, wherein the pixel definition layer is a hydrophobic pixel definition layer.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 1, further comprising the following steps:

A flat layer is prepared on the TFT backplane, and the pixel definition layer and the anode are both located on the flat layer.
The method for preparing an inkjet printed AMOLED display panel according to claim 1, wherein the forming an ink layer on the anode by inkjet printing is specifically:

A hole layer and a light emitting layer are sequentially formed on the anode by inkjet printing; wherein the hole layer includes a hole injection layer and a hole transport layer, and the hole transport layer is located at the hole injection. Between the layer and the light emitting layer.
A method for preparing an inkjet printed AMOLED display panel includes the following steps:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

Preparing a spacer layer on the anode to isolate the anode from the pixel definition layer;

Preparing a pixel definition layer on the TFT backplane, and the pixel definition layer covers the spacer layer;

Patterning the pixel definition layer and forming a gap on the pixel definition layer to expose the spacer layer;

Etching the spacer layer under the notch through an etching solution to expose the anode;

Forming an ink layer on the anode by means of inkjet printing;

The thickness of the spacer layer ranges from 300 to 800 Å;

The spacer layer is a metal film layer, and the anode is a transparent electrode or a reflective electrode.
The method for preparing an inkjet printed AMOLED display panel according to claim 11, wherein the transparent electrode is a layer of ITO film, and the reflective electrode comprises two layers of ITO film and sandwiched between the two layers of ITO film Silver metal layer between layers.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 12, further comprising the following steps after patterning the pixel definition layer:

A baking process is performed on the pixel definition layer and the anode.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 13, wherein the spacer layer is a molybdenum film layer or an aluminum film layer, and the spacer layer under the notch is etched away by an aluminum etching solution.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 11, wherein the pixel definition layer is patterned by a yellow light process;

The pixel definition layer is a hydrophobic pixel definition layer.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 11, further comprising the following steps:

Preparing a flat layer on the TFT backplane, and the pixel definition layer and the anode are located on the flat layer;

Forming an ink layer on the anode by inkjet printing is specifically:

A hole layer and a light emitting layer are sequentially formed on the anode by inkjet printing; wherein the hole layer includes a hole injection layer and a hole transport layer, and the hole transport layer is located at the hole injection. Between the layer and the light emitting layer.
A method for preparing an inkjet printed AMOLED display panel includes the following steps:

Preparing a TFT backplane, and preparing an anode on the TFT backplane;

Preparing a spacer layer on the anode to isolate the anode from the pixel definition layer;

A pixel definition layer is prepared on the TFT backplane, and the pixel definition layer covers the spacer layer; the pixel definition layer is a hydrophobic pixel definition layer;

Patterning the pixel definition layer and forming a gap on the pixel definition layer to expose the spacer layer;

Etching the spacer layer under the notch through an etching solution to expose the anode;

Forming an ink layer on the anode by means of inkjet printing;

Forming an ink layer on the anode by inkjet printing is specifically:

A hole layer and a light emitting layer are sequentially formed on the anode by inkjet printing; wherein the hole layer includes a hole injection layer and a hole transport layer, and the hole transport layer is located at the hole injection. Between the layer and the light emitting layer.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 17, wherein the thickness of the spacer layer ranges from 300 to 800 Angstroms;

The spacer layer is a metal film layer, and the anode is a transparent electrode or a reflective electrode.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 18, wherein the transparent electrode is a layer of ITO film, and the reflective electrode comprises two layers of ITO film and sandwiched between the two layers of ITO film Silver metal layer between layers;

After graphicizing the pixel definition layer, the following steps are further included:

Performing a baking process on the pixel definition layer and the anode;

The spacer layer is a molybdenum film layer or an aluminum film layer, and the spacer layer under the notch is etched away by an aluminum etching solution.
The method for manufacturing an inkjet printed AMOLED display panel according to claim 17, wherein the pixel definition layer is patterned by a yellow light process;

The method for preparing an inkjet printed AMOLED display panel further includes the following steps:

A flat layer is prepared on the TFT backplane, and the pixel definition layer and the anode are both located on the flat layer.